The present study provides empirical support for a new interpersonal concept of transactional escalation. This proposition hypothesizes that an individual's typical pattern of interpersonal behaviour will become more extreme and rigid under stressful interpersonal conditions. Thirty Caucasian females participated in brief interviews that had two stages: low-stress and high-stress conditions. The half of the subjects who were assigned to a high-stress interview condition were predicted to show an escalation of their typical friendly-submissive patterns during the second half of the interview. Findings revealed that escalation was evidenced by an increase in the extremeness and rigidity of their interpersonal behaviour. Implications for interpersonal theory, and for diagnostic and psychotherapy endeavours are discussed and directions for future research are provided.